Events in Classical Reporting

Events in Classical Reports

• Classical Reports are basic type of reports, where not much functionality is given to the user. 
• ABAP language is an event-driven language which means it is executed based on different events and not line by line.

Below are some events in classical reporting :-

1. INITIALIZATION

• This event is triggered before the selection screen is called.
• This event is used to pass some initial values to the variables, set default values.
• It is basically used with Select-Options , to pass some initial values. 

Example:- 

INITIALIZATION.

S_Date-low = sy-datum.    "set the lower limit of the range to the system's date

append s_date. 

       2. At Selection Screen

• This event is used to validate more than one fields on the selection screen.
• Validating is essential to stop the program flow at the very moment where an error occurs i.e an invalid value is entered. 

Syntax:- AT SELECTION_SCREEN.

       3. At Selection Screen On

• This event is used to validate only a field provided in the syntax. 
• Whenever an invalid value is entered and executed, the corresponding field gets highlighted and rest of the fields are disabled.

Syntax:- AT SELECTION-SCREEN ON <parameter_name>.

      4. Start of Selection

The actual selection logic is written under the start of selection event.

Syntax:- START-OF-SELECTION.

      5. Top Of Page

To print heading on every page in the report.

Syntax:- TOP-OF-PAGE.

     6. End Of Page

To print footer on every page in the report.

Syntax:- END-OF-PAGE.

     7. End of Selection

• The END-OF-SELECTION event is triggered in type executable programs once the logical database has finished reading all data and before the list processor is started.
• It tells the server that all the database reading is completed and no further reading is going to take place.

Syntax:- END-OF-SELECTION.